export default {
	namespaced: true,
	
	state: () => ({
		// 每个商品的信息对象，都包含如下 6 个属性：
		// { goods_id, goods_name, goods_price, goods_count, goods_small_logo, goods_state }
		    
		cart: JSON.parse(uni.getStorageSync('cart') || '[]')
	}),
	
	
	mutations: {
		addToCart(state, goods) {
			const findResult = state.cart.find(x => x.goods_id === goods.goods_id)

			if (!findResult) {
				state.cart.push(goods)
			}else {
				findResult.goods_count++
			}
			
			this.commit('m_cart/saveToStorage')
		},
		
		saveToStorage(state) {
			uni.setStorageSync('cart', JSON.stringify(state.cart))
		},
		
		// 更新购物车中的商品的勾选状态
		updateGoodsState(state, goods) {
			const findResult = state.cart.find(x => x.goods_id === goods.goods_id)
			
			if (findResult) {
				findResult.goods_state = goods.goods_state
				
				this.commit('m_cart/saveToStorage')
			}
		},
		
			
		updataGoodsCount(state, goods) {
			const findResult = state.cart.find(x => x.goods_id === goods.goods_id)
			if (findResult) {
				findResult.goods_count = goods.goods_count
				
				this.commit('m_cart/saveToStorage')
			}
		},
		
		removeGoodsById(state, goods_id) {
			state.cart = state.cart.filter(x => x.goods_id !== goods_id)
			
			
			this.commit('m_cart/saveToStorage')
		},
		
		// 更新购物车中所有商品的勾选状态
		updataAllGoodState(state, newState) {
			state.cart.forEach(x => x.goods_state = newState)
			
			this.commit('m_cart/saveToStorage')
		}
	},
	
	getters: {
		total(state) {
			// let c = 0
			// state.cart.forEach(x => c += x.goods_count)
			// return c
			
			return state.cart.reduce((total, item) => total += item.goods_count, 0)
		},
		
		checkedCount(state) {
			return state.cart.filter(x => x.goods_state).reduce((total, item) => total += item.goods_count, 0)
		},
		
		checkGoodsAmount(state) {
			// 先使用filter方法，从购物车中过滤器已勾选的商品
			// 使用reduce 方法， 将已勾选的商品数量 * 单价之后，进行累加
			// reduce() 的返回值就是已勾选的商品的总价
			// 最后调用toFixed(2)方法，保留两位小数
			return state.cart.filter(x => x.goods_state)
						.reduce((totoal, item) => totoal += item.goods_count * item.goods_price, 0)
						.toFixed(2)
		}
	}
}